arch/s390/kernel/irq.c

   1 /*
   2  *    Copyright IBM Corp. 2004, 2011
   3  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   4  *               Holger Smolinski <Holger.Smolinski@de.ibm.com>,
   5  *               Thomas Spatzier <tspat@de.ibm.com>,
   6  *
   7  * This file contains interrupt related functions.
   8  */
   9
  10 #include <linux/kernel_stat.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/proc_fs.h>
  14 #include <linux/profile.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/ftrace.h>
  18 #include <linux/errno.h>
  19 #include <linux/slab.h>
  20 #include <linux/cpu.h>
  21 #include <linux/irq.h>
  22 #include <asm/irq_regs.h>
  23 #include <asm/cputime.h>
  24 #include <asm/lowcore.h>
  25 #include <asm/irq.h>
  26 #include <asm/hw_irq.h>
  27 #include "entry.h"
  28
  29 DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
  30 EXPORT_PER_CPU_SYMBOL_GPL(irq_stat);
  31
  32 struct irq_class {
  33         int irq;
  34         char *name;
  35         char *desc;
  36 };
  37
  38 /*
  39  * The list of "main" irq classes on s390. This is the list of interrupts
  40  * that appear both in /proc/stat ("intr" line) and /proc/interrupts.
  41  * Historically only external and I/O interrupts have been part of /proc/stat.
  42  * We can't add the split external and I/O sub classes since the first field
  43  * in the "intr" line in /proc/stat is supposed to be the sum of all other
  44  * fields.
  45  * Since the external and I/O interrupt fields are already sums we would end
  46  * up with having a sum which accounts each interrupt twice.
  47  */
  48 static const struct irq_class irqclass_main_desc[NR_IRQS_BASE] = {
  49         {.irq = EXT_INTERRUPT,  .name = "EXT"},
  50         {.irq = IO_INTERRUPT,   .name = "I/O"},
  51         {.irq = THIN_INTERRUPT, .name = "AIO"},
  52 };
  53
  54 /*
  55  * The list of split external and I/O interrupts that appear only in
  56  * /proc/interrupts.
  57  * In addition this list contains non external / I/O events like NMIs.
  58  */
  59 static const struct irq_class irqclass_sub_desc[] = {
  60         {.irq = IRQEXT_CLK, .name = "CLK", .desc = "[EXT] Clock Comparator"},
  61         {.irq = IRQEXT_EXC, .name = "EXC", .desc = "[EXT] External Call"},
  62         {.irq = IRQEXT_EMS, .name = "EMS", .desc = "[EXT] Emergency Signal"},
  63         {.irq = IRQEXT_TMR, .name = "TMR", .desc = "[EXT] CPU Timer"},
  64         {.irq = IRQEXT_TLA, .name = "TAL", .desc = "[EXT] Timing Alert"},
  65         {.irq = IRQEXT_PFL, .name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  66         {.irq = IRQEXT_DSD, .name = "DSD", .desc = "[EXT] DASD Diag"},
  67         {.irq = IRQEXT_VRT, .name = "VRT", .desc = "[EXT] Virtio"},
  68         {.irq = IRQEXT_SCP, .name = "SCP", .desc = "[EXT] Service Call"},
  69         {.irq = IRQEXT_IUC, .name = "IUC", .desc = "[EXT] IUCV"},
  70         {.irq = IRQEXT_CMS, .name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  71         {.irq = IRQEXT_CMC, .name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  72         {.irq = IRQEXT_FTP, .name = "FTP", .desc = "[EXT] HMC FTP Service"},
  73         {.irq = IRQIO_CIO,  .name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  74         {.irq = IRQIO_QAI,  .name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt"},
  75         {.irq = IRQIO_DAS,  .name = "DAS", .desc = "[I/O] DASD"},
  76         {.irq = IRQIO_C15,  .name = "C15", .desc = "[I/O] 3215"},
  77         {.irq = IRQIO_C70,  .name = "C70", .desc = "[I/O] 3270"},
  78         {.irq = IRQIO_TAP,  .name = "TAP", .desc = "[I/O] Tape"},
  79         {.irq = IRQIO_VMR,  .name = "VMR", .desc = "[I/O] Unit Record Devices"},
  80         {.irq = IRQIO_LCS,  .name = "LCS", .desc = "[I/O] LCS"},
  81         {.irq = IRQIO_CTC,  .name = "CTC", .desc = "[I/O] CTC"},
  82         {.irq = IRQIO_APB,  .name = "APB", .desc = "[I/O] AP Bus"},
  83         {.irq = IRQIO_ADM,  .name = "ADM", .desc = "[I/O] EADM Subchannel"},
  84         {.irq = IRQIO_CSC,  .name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  85         {.irq = IRQIO_PCI,  .name = "PCI", .desc = "[I/O] PCI Interrupt" },
  86         {.irq = IRQIO_MSI,  .name = "MSI", .desc = "[I/O] MSI Interrupt" },
  87         {.irq = IRQIO_VIR,  .name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
  88         {.irq = IRQIO_VAI,  .name = "VAI", .desc = "[I/O] Virtual I/O Devices AI"},
  89         {.irq = NMI_NMI,    .name = "NMI", .desc = "[NMI] Machine Check"},
  90         {.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"},
  91 };
  92
  93 void __init init_IRQ(void)
  94 {
  95         BUILD_BUG_ON(ARRAY_SIZE(irqclass_sub_desc) != NR_ARCH_IRQS);
  96         init_cio_interrupts();
  97         init_airq_interrupts();
  98         init_ext_interrupts();
  99 }
 100
 101 void do_IRQ(struct pt_regs *regs, int irq)
 102 {
 103         struct pt_regs *old_regs;
 104
 105         old_regs = set_irq_regs(regs);
 106         irq_enter();
 107         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 108                 /* Serve timer interrupts first. */
 109                 clock_comparator_work();
 110         generic_handle_irq(irq);
 111         irq_exit();
 112         set_irq_regs(old_regs);
 113 }
 114
 115 /*
 116  * show_interrupts is needed by /proc/interrupts.
 117  */
 118 int show_interrupts(struct seq_file *p, void *v)
 119 {
 120         int index = *(loff_t *) v;
 121         int cpu, irq;
 122
 123         get_online_cpus();
 124         if (index == 0) {
 125                 seq_puts(p, "           ");
 126                 for_each_online_cpu(cpu)
 127                         seq_printf(p, "CPU%d       ", cpu);
 128                 seq_putc(p, '\n');
 129         }
 130         if (index < NR_IRQS_BASE) {
 131                 seq_printf(p, "%s: ", irqclass_main_desc[index].name);
 132                 irq = irqclass_main_desc[index].irq;
 133                 for_each_online_cpu(cpu)
 134                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 135                 seq_putc(p, '\n');
 136                 goto out;
 137         }
 138         if (index > NR_IRQS_BASE)
 139                 goto out;
 140
 141         for (index = 0; index < NR_ARCH_IRQS; index++) {
 142                 seq_printf(p, "%s: ", irqclass_sub_desc[index].name);
 143                 irq = irqclass_sub_desc[index].irq;
 144                 for_each_online_cpu(cpu)
 145                         seq_printf(p, "%10u ",
 146                                    per_cpu(irq_stat, cpu).irqs[irq]);
 147                 if (irqclass_sub_desc[index].desc)
 148                         seq_printf(p, "  %s", irqclass_sub_desc[index].desc);
 149                 seq_putc(p, '\n');
 150         }
 151 out:
 152         put_online_cpus();
 153         return 0;
 154 }
 155
 156 unsigned int arch_dynirq_lower_bound(unsigned int from)
 157 {
 158         return from < NR_IRQS_BASE ? NR_IRQS_BASE : from;
 159 }
 160
 161 /*
 162  * Switch to the asynchronous interrupt stack for softirq execution.
 163  */
 164 void do_softirq_own_stack(void)
 165 {
 166         unsigned long old, new;
 167
 168         old = current_stack_pointer();
 169         /* Check against async. stack address range. */
 170         new = S390_lowcore.async_stack;
 171         if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 172                 /* Need to switch to the async. stack. */
 173                 new -= STACK_FRAME_OVERHEAD;
 174                 ((struct stack_frame *) new)->back_chain = old;
 175                 asm volatile("   la    15,0(%0)\n"
 176                              "   brasl 14,__do_softirq\n"
 177                              "   la    15,0(%1)\n"
 178                              : : "a" (new), "a" (old)
 179                              : "0", "1", "2", "3", "4", "5", "14",
 180                                "cc", "memory" );
 181         } else {
 182                 /* We are already on the async stack. */
 183                 __do_softirq();
 184         }
 185 }
 186
 187 /*
 188  * ext_int_hash[index] is the list head for all external interrupts that hash
 189  * to this index.
 190  */
 191 static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 192
 193 struct ext_int_info {
 194         ext_int_handler_t handler;
 195         struct hlist_node entry;
 196         struct rcu_head rcu;
 197         u16 code;
 198 };
 199
 200 /* ext_int_hash_lock protects the handler lists for external interrupts */
 201 static DEFINE_SPINLOCK(ext_int_hash_lock);
 202
 203 static inline int ext_hash(u16 code)
 204 {
 205         BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 206
 207         return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 208 }
 209
 210 int register_external_irq(u16 code, ext_int_handler_t handler)
 211 {
 212         struct ext_int_info *p;
 213         unsigned long flags;
 214         int index;
 215
 216         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 217         if (!p)
 218                 return -ENOMEM;
 219         p->code = code;
 220         p->handler = handler;
 221         index = ext_hash(code);
 222
 223         spin_lock_irqsave(&ext_int_hash_lock, flags);
 224         hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 225         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 226         return 0;
 227 }
 228 EXPORT_SYMBOL(register_external_irq);
 229
 230 int unregister_external_irq(u16 code, ext_int_handler_t handler)
 231 {
 232         struct ext_int_info *p;
 233         unsigned long flags;
 234         int index = ext_hash(code);
 235
 236         spin_lock_irqsave(&ext_int_hash_lock, flags);
 237         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 238                 if (p->code == code && p->handler == handler) {
 239                         hlist_del_rcu(&p->entry);
 240                         kfree_rcu(p, rcu);
 241                 }
 242         }
 243         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 244         return 0;
 245 }
 246 EXPORT_SYMBOL(unregister_external_irq);
 247
 248 static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 249 {
 250         struct pt_regs *regs = get_irq_regs();
 251         struct ext_code ext_code;
 252         struct ext_int_info *p;
 253         int index;
 254
 255         ext_code = *(struct ext_code *) &regs->int_code;
 256         if (ext_code.code != EXT_IRQ_CLK_COMP)
 257                 set_cpu_flag(CIF_NOHZ_DELAY);
 258
 259         index = ext_hash(ext_code.code);
 260         rcu_read_lock();
 261         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 262                 if (unlikely(p->code != ext_code.code))
 263                         continue;
 264                 p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 265         }
 266         rcu_read_unlock();
 267         return IRQ_HANDLED;
 268 }
 269
 270 static struct irqaction external_interrupt = {
 271         .name    = "EXT",
 272         .handler = do_ext_interrupt,
 273 };
 274
 275 void __init init_ext_interrupts(void)
 276 {
 277         int idx;
 278
 279         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 280                 INIT_HLIST_HEAD(&ext_int_hash[idx]);
 281
 282         irq_set_chip_and_handler(EXT_INTERRUPT,
 283                                  &dummy_irq_chip, handle_percpu_irq);
 284         setup_irq(EXT_INTERRUPT, &external_interrupt);
 285 }
 286
 287 static DEFINE_SPINLOCK(irq_subclass_lock);
 288 static unsigned char irq_subclass_refcount[64];
 289
 290 void irq_subclass_register(enum irq_subclass subclass)
 291 {
 292         spin_lock(&irq_subclass_lock);
 293         if (!irq_subclass_refcount[subclass])
 294                 ctl_set_bit(0, subclass);
 295         irq_subclass_refcount[subclass]++;
 296         spin_unlock(&irq_subclass_lock);
 297 }
 298 EXPORT_SYMBOL(irq_subclass_register);
 299
 300 void irq_subclass_unregister(enum irq_subclass subclass)
 301 {
 302         spin_lock(&irq_subclass_lock);
 303         irq_subclass_refcount[subclass]--;
 304         if (!irq_subclass_refcount[subclass])
 305                 ctl_clear_bit(0, subclass);
 306         spin_unlock(&irq_subclass_lock);
 307 }
 308 EXPORT_SYMBOL(irq_subclass_unregister);